1. Earth Science Ch. 1
Mapping the Earth

2. Representing Earth’s Surface
Latitude
Latitude is distance North and South of the Equator.
The Equator is 0° latitude. The poles are 90° latitude.
The equator is the only line of latitude that divides the earth into equal halves.
Lines of latitude are called parallels.
The size of a degree of latitude is always the same
1˚= 69 miles
Latitude is determined by the angle of the north star (Polaris) above the horizon
Latitude of Bluefield VA: 37° N

3. Longitude Longitude is distance East and West of the Prime Meridian
The longitude line designated 0° is the Prime Meridian.
Lines of longitude are called meridians
All meridians split a globe into 2 equal halves.
The size of a degree of longitude changes. The largest distance is at the equator. The smallest distance is at the poles.
Longitude of Bluefield VA: 81° W

5. Both latitude and longitude are measured in degrees, minutes, and seconds.
One degree is divided into 60’ (minutes)
One minute is divided into 60” (seconds)

6. How does the international date line work?
Passes through the mid Pacific Ocean
180˚ longitude
When you cross the line going west, its one day later.
When you cross the line going east, its one day earlier.

7. Globes and Maps
A globe is the most accurate representation of the earth.
A map or projection is a flat representation of the earth’s surface.
All flat maps originally have distortions because you are projecting a round surface onto a flat surface.

8. There are 4 types of map projections:
Mercator
Robinson
Conic
Gnomonic

9. Mercator Used for navigation.
Lines of latitude and longitude are parallel.
Sizes and distances are distorted.
Directions are shown accurately.
Produced by placing a cylinder of paper around a globe.
Distortion occurs as you move toward the poles.

10. Robinson Most accurate map projection.
Most distances, sizes, and shapes are accurate.
Distortion only occurs around the edges.

11. Conic Very accurate over small areas.
Used to make road and weather maps.
Cone of paper is placed on a globe at a line of latitude.

12. Gnominic
Useful for navigation because the shortest distance between 2 points is very accurate.
Distances and directions are distorted.
Created by one piece of paper touching one point on the globe.

13. Features of a Topographic Map (elevation)
Contour lines: connect points of equal elevation
Contour interval: the distance between one contour line and the next
Index contours: darker lines making elevation easier to determine, every 5th line
Relief: Distance between the lowest and highest points on a map
Hachured marks: represent a depression
Valleys: represented by a V-shape on a map
Mountain tops: represented by the smallest complete circle on a map.
Lines that are close together represent a steep slope
Lines that are farther apart represent a gradual slope

14. Index Contour
Contour Lines
Steep slope
Hilltop
Valley
Gradual Slope

15. Hatchured Lines Represent Depressions How to read hatchured lines

16. Match the topographic map to the correct profileB E D C F A

17. Scale
The scale of a map compares the actual distance to the distance on a map.
The most common scale used in geology is the 7.5 minute quadrangle.
The scale is 1: 24,000
Both units remain the same unless noted on the map.

18. Geologic Maps
A map that shows the type and age of exposed rock

19. GPS
The process of collecting data from satellites is called remote sensing.
Remote sensing is used for GPS
GPS stands for Global Positioning Systems
GPS receives information from satellites to compute latitude, longitude, speed, direction, and elevation
In order to find locations, GPS devices receive information from 4 satellites.
GPS is not only used in navigation but is also used in Earth Science for the study of features on Earth’s surface.

20. How GPS Finds Location